One and a half billion years ago, Missouri’s interior was dominated by towering volcanoes and shallow seas.
Time and erosion have changed the landscape, but those geologic processes left reminders of that time: layers of limestone, the St. Francois mountains — and potentially, billions of dollars in mineral resources.
As the world races to find more of the elements modern technology relies on, experts think those ancient deposits could make Missouri the new center of a booming industry.
Carey Bridges, state geologist with the Missouri Geological Survey, works with researchers in industry and academia to assess Missouri’s potential as a domestic source for so-called “critical minerals." The U.S. Geological Survey considers a mineral “critical” if it’s necessary for modern technology, but its access is vulnerable to trade disputes and disruptions.
“Some people think we're flyover country, we must be flat, but I feel like Missouri has really interesting geology and geography across the state,” Bridges said. “That permissive geology resulted in a lot of these minerals being present here. It's really been a target for scientists to study and try to locate some of these deposits.”
The USGS list of critical minerals is re-evaluated every two years, as per the Energy Act of 2020, and the most recent was released in November 2025. More than half of the sixty minerals on the list have known deposits in Missouri, including cobalt, lead, copper, and a number of rare earth elements — materials used in renewable energy technology and consumer electronics.
Bridges said the investment in developing Missouri’s mineral production could help make the market for these resources more stable.
“It certainly reduces our vulnerability to rely on foreign sources,” she said. “And so if we have that source or that resource domestically, then we don't have to worry about price fluctuations, about embargoes of trade.”
One rare earth project, owned by St. Louis-based Caldera Holdings, is just outside the small town of Sullivan, Missouri.
The Pea Ridge iron mine opened in the 1950s, and produced iron ore for decades, until America’s shrinking steel industry left the mine with few buyers. By the 2000s Pea Ridge went bankrupt and was abandoned. But the mine was left with deposits of rare earth elements, clinging to unprocessed rock underground and swimming in the toxic lakes outside.
Rare earth elements are not, geologically speaking, actually very rare. They can be found in many places around the world, but often in concentrations too low for a mine to be economically viable. That’s what makes them so expensive to produce — and so potentially valuable for producers.
Caldera Holdings chairman James Kennedy said their partners are preparing to invest more than $1 billion in returning Pea Ridge to a functioning mine. He said he worries, though, that the amount of hype government investment surrounding rare earth elements will flood the market with new mining operations.
“Money follows the story, and the story's exciting, but reality is always behind the curtain,” Kennedy said. “I predict that this instability is going to cause a lot of trouble for people who are spending billions of dollars in this space.”
To shield the operation from price changes, Caldera is planning to diversify the materials Pea Ridge will produce. Phosphate, which is used in agricultural fertilizers, is intended to make up a large proportion of the mine’s revenue.
But first, Caldera will attempt to pull out whatever valuable minerals it can from the previous mining operation’s waste, hoping to turn a profit from those extractions before eventually heading back underground.
“We'll never make the mistake of the past, and we'll never throw those materials away because in the end, they're actually worth more than the iron,” Kennedy said.
The idea behind that process is two-fold. First, re-processing the waste from the iron-producing days will help the contaminated water reach the EPA’s guidelines for mine waste water. Second, the compounds contaminating that water are rich with the kinds of rare earth elements that American industries need.
“The pollutants are the money,” Kennedy said.
As Missouri’s critical mineral deposits have drawn national attention, local concerns about the health and environmental impacts of mining have resurfaced. At the University of Missouri Science and Technology’s Center for Critical Minerals, researchers have surveyed communities in the “Old Lead Belt” region where much of the critical mineral mining would take place.
Associate director Michael Moats said the team has found many people are open to a mining revival in the area, anxious to expand economies and employment opportunities. He also said that America’s comparatively strict environmental regulations should, in theory, protect Missourians from the worst impacts of critical mineral mining.
“If they go to countries with less stringent environmental rules, we're polluting our planet. Maybe it's not in my backyard, and I'm very happy about that — I get my materials and I don't have to look at the pollution or deal with it,” Moats said. “I think that's wrong.”
Even if Missouri becomes a major source of rare earth and critical mineral ores, Chinese manufacturers still do the majority of the processing that turns those ores into usable materials.
The center has researched the development of those processing facilities in Missouri, something Moats says could reinvigorate the rural economies surrounding deposits.
“The counties that we're helping are some of the poorest counties in the state of Missouri,” Moats said. “I grew up in Dent County, I went to high school here in Rolla. I know people who live in these counties personally. They're just looking for a good way of life with a good paying job. And if we can help them do that, then that's a real motivator to me.”
Estimates from the center predict more than $34 billion in economic development, and 23,000 new jobs, from Missouri’s critical mineral sector in the next ten years.
